Effects of electrical stimulation of olfactory bulb on proliferation, migration and differentiation of neural stem cells in subventricular zone

Abstract

Objective To investigate the effects of electrical stimulation of olfactory bulb( OB) on the proliferation, migration and differentiation of neural stem cell ( NSC ) in subventricular zone. Method Forty - eight adult female Sprague - Dawley(SD) rats were randomly divided into control group, sham stimulation group and stimulation group including 6 time points(1 day,3 day,7 day, 14 day,21 day, 28 day). The rats were injected intraperitoneally with bromodeoxyuridine( BrdU) to detect the proliferation of NSC by immunohistochemistry staining. Another 18 rats were randomly divided into control group, sham stimulation group and stimulation group. Four weeks after BrdU injection, the rats were sacrificed and immunohistochemistry and immunofluorescence were used to investigate the migration and differentiation of NSC in OB. Results In SVZ, BrdU - positive cells began to increase 1 d after stimulation (17. 67 ± 1.03, P <0.01) .reached to the maximum level at 1 week(28. 50 ± 1. 87, P <0. 01) ,then decreased to normal at 3 week. Four weeks after injection of BrdU,the BrdU -positive cells significantly increased in RMS(67. 33 ±3.50, P <0.01) and OB(44.33 ±5.47, P <0.01) in stimulation group. Fluorescence double staining showed that the stimulation of OB had no effect on the differentiation of NSC into neurons or gliocytes. Conclusions Electrical stimulation of OB could promote proliferation, migration of NSC in SVZ, but it has no effect on the differentiation of NSC into neurons or gliocytes. Key words: Electrical stimulation; Olfactory bulb; Neurogenesis; Rats